 Joined: 11/07/2010(UTC) Posts: 908 Location: Wine Country, CA
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A quick question concerning digital conversions and LEDs for lights. Is there a typical voltage range that the marklin and esu decoders provide for locomotive lighting? I am planning on converting some of my locomotives to LEDs and I wanted to know what size resistor I should use. Also, I am assuming that using 1.5 volt LEDs won't cause any problems with the marklin or esu decoders.
I know it is a simple question but I appreciate the help on this one.
Thanks for the help.
Chris
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Joined: 28/02/2011(UTC)
Posts: 6
Location: Lithgow NSW Australia
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Chris
I have converted many locos to DCC. I mainly use ESU decoders and always replace light bulbs with LEDs. I don't know the voltage in the decoder's lighting circuits but assume it is the operational voltage of the deceder.
I always insert a quarter (.25) watt 1K ohme resistor in the circuit, usually on the blue wire which is the common return for all decoder functions. So far, I have not had any burnt-out LEDs.
Hope this will assist you.
Geoff
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Joined: 28/02/2011(UTC)
Posts: 6
Location: Lithgow NSW Australia
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Chris
Please accept my apolagies for misleading you in my pevious post. I had a moment of doubt and went to the shed to check. I use half (0.5) watt, not quarter (0.25) watt, 1K ohme resistors.
Geoff
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 Joined: 16/02/2004(UTC) Posts: 6,803 Location: Cologne, NRW
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Originally Posted by: Chris6382chris  Is there a typical voltage range that the marklin and esu decoders provide for locomotive lighting? Expect the "light voltage" to be about 2 V below track voltage. I would calculate resistors for a light voltage of 22 V. Wattage of the resistor can be calculated based on the LED power consumption (.25 W for low current LEDs (10 mA), .5 W for normal LEDs (20 mA)). 1 kOhm is fine for 20 mA LEDs. |
Regards
Tom
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Suaviter in modo, fortiter in re |
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Joined: 11/07/2010(UTC) Posts: 908 Location: Wine Country, CA
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Thanks to both of you for the quick replies. Very helpful information.
Chris
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Joined: 20/10/2011(UTC)
Posts: 3
Location: london
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I tried this using a load compensator from superbrightleds.
It did not work. I used 1156 orange colored LED’s that are visually clear when off. The LED’s are about 1 year old, never installed
until yesterday. They may be bad, but that's doubtful because neither worked.
Has anyone done this? Am I missing something? I could have wired the load compensator wrong, but that is not likely because there are only two wires to tap.
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Joined: 10/02/2006(UTC) Posts: 2,032
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I use 12V for my layout lighting and have calculated the resistance for various combinations of LED. See the table at http://layout.mixmox.com/1/ResistorsFirst you need to measure the voltage you have from the decoder... then calculate the resistance to give you the mA you desire. Knowing the voltages lets you ensure that your LEDs are not too bright or too dim... |
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Joined: 16/02/2004(UTC) Posts: 6,803 Location: Cologne, NRW
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Originally Posted by: DaleSchultz Knowing the voltages lets you ensure that your LEDs are not too bright or too dim...
Bear in mind that voltages vary from controller to controller, so assume the highest voltage that can be expected. |
Regards
Tom
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Suaviter in modo, fortiter in re |
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